Image processing apparatus capable of varying magnification of images and method of using same

Abstract

The present invention relates to an image processing apparatus for carrying out a variable scale magnification processing for contracting or enlarging an original image. The image processing apparatus including a variable scale moving unit for increasing pixels in accordance with a variable scale magnification in order to enlarge the original image includes a smoothing processing unit for smoothing pixel data. The smoothing processing unit detects the number of increased pixels for each pixel by an increased pixel number determining unit, so as to smooth image data output from the variable scale magnification moving unit by employing smoothing filters of a matrix size selected in accordance with the result of the detection. This results in an image processing apparatus that can prevent a degradation in image quality by an appropriate smoothing processing independently of whether a variable scale magnification in enlargement is integer or not.

What is claimed is: 
     
       1. An image processing apparatus for processing image data including a number of pixel data, comprising: enlarging means for increasing the number of pixel data by repeating respective pixel data a number of repeat times to enlarge an image, wherein the number of said repeat times is determined for each of said pixel data;   a plurality of smoothing filters which have different matrix sizes in one dimension from each other; and   smoothing means for selecting, individually for each of said pixel data, one of said smoothing filters in accordance with said number of the repeat times of each of said pixel data, said selected smoothing filter having a matrix size in said one dimension which is not less than the said number of the repeat times, and for filtering each of said pixel data by using said selected smoothing filter, wherein the smoothing means includes means for selecting different smoothing filters for different pixels within the same image in accordance with said number of the repeat times.   
     
     
       2. The image processing apparatus according to claim 1, further comprising: input means for inputting an enlarging rate; and   determining means for determining said number of the repeat times for each of said pixel data in accordance with said enlarging rate input by said input means, wherein   said enlarging means increases the number of said pixel data in accordance with said number of repeat times determined by said determining means, and   said smoothing means selects said smoothing filter in accordance with said determined number of the repeat times.   
     
     
       3. The image processing apparatus according to claim 1, wherein said smoothing filters have different intensities of smoothing from each other. 
     
     
       4. The image processing apparatus of claim 1, further comprising an image data input means for inputting image data. 
     
     
       5. The image processing apparatus of claim 1, further comprising a memory, wherein the memory contains image data. 
     
     
       6. The image processing apparatus of claim 1, wherein the enlarging means comprises a variable scale magnification unit having a clock generating circuit and a memory. 
     
     
       7. The image processing apparatus of claim 1, wherein the enlarging means enlarges the image by a noninteger multiple. 
     
     
       8. An image processing apparatus for processing image data including a number of pixel data, comprising: enlarging means for increasing the number of pixel data by repeating respective pixel data a number of repeat times to enlarge an image, wherein the number of said repeat times is determined for each of said pixel data;   a plurality of smoothing filters for filtering one of said pixel data which corresponds to a central pixel with reference to pixel data which correspond to a plurality of peripheral pixels adjacent to said central pixel, wherein each of said plural smoothing filters refers to a different number of peripheral pixels; and   smoothing means for selecting, individually for each of said pixel data, one of said smoothing filters in accordance with said number of the repeat times of each of said pixel data, said selected smoothing filter referring to a number of peripheral pixels which is not less than the number of repeat times, and for filtering each of said pixel data by using said selected smoothing filter, wherein the smoothing means includes means for selecting different smoothing filters for different pixels within the same image in accordance with said number of the repeat times.   
     
     
       9. The image processing apparatus of claim 8, wherein the enlarging means enlarges the image by a noninteger multiple. 
     
     
       10. An image processing method for enlarging image data including a number of pixel data at an arbitrary enlarging rate, comprising the steps of: repeating each of said pixel data a plural number of repeat times corresponding to said enlarging rate, wherein said number of repeat times is determined for each of said pixel data;   detecting the plural number of repeat times for each of said pixel data;   selecting, individually for each of said pixel data, a smoothing filter having a size in one dimension which is not less than said number of repeat times for each of said pixel data, wherein different smoothing filters may be selected for different pixels within the same image and in accordance with said number of repeat times of each of said pixel data; and   correcting an intensity value of each of said pixel data by referring to pixel data adjacent to said pixel data to be corrected by using said selected smoothing filter.   
     
     
       11. The image processing method of claim 10, wherein the arbitrary enlarging rate has a noninteger multiple. 
     
     
       12. The image processing method of claim 10, further comprising the step of outputting image data of an enlarged size document with corrected intensity values for each pixel. 
     
     
       13. The image processing method of claim 12, further comprising the step of inputting image data from an original size document including a number of pixel data. 
     
     
       14. An image processing system comprising: means for magnifying pixel data by repeating respective pixel data a number of times equal to a magnification factor M, wherein M is determined for each pixel;   a plurality of smoothing filters of different matrix sizes; and   means for selecting individually for each of said pixel data, a different one of said smoothing filters in accordance with the number of repeat times of each of said pixel data having a matrix size m×n, where at least one of m and n is not less than M to smooth said repeated pixel data.   
     
     
       15. The image processing system of claim 14, wherein said at least one of m and n satisfy the following relationship:   M≦(m or n)≦M+1.